Combination bolt holding and cartridge feeding device for a magazine-type firearm



Feb. 4, 1964 F. P. RE COMBINATION BOLT HOLDING AND CARTRIDGE FEEDING DEVICE FOR A MAGAZINE-TYPE FIREARM Filed Aug. 20, 1962 Fig .1

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United States Patent C) 3,120,070 COMBINATION BOLT HOLDING AND CARTRIDGE FEEDING DEVICE FOR A MAGAZINE-TYPE FIREARM Frederick P. Reed, Ludlow, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed Aug. 20, 1962, Ser. No. 218,184 Claims. (Cl. 42 18) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to magazine-fed firearms of the blowback type and pertains more particularly to devices for indexing cartridges fed from the magazine into the receiver at a firing position and to devices for releasably holding the bolt in battery position.

It is one object of this invention to provide for a simply constructed and expendable firearm a bolt holding device and a cartridge indexing device which are simple in construction, easy to manufacture and positive in operation.

It is another object of this invention to form from the firearm trigger guard a cantilever type spring designed to perform the functions of indexing the feeding position cartridge, accelerating the feeding position cartridge to the barrel chamber prior to contact by the bolt during displacement thereof to battery position, and releasably holding the bolt in battery position.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a longitudinally cross-sectioned view of a firearm receiver showing the bolt in battery position;

FIG. 2 is a view similar to FIG. 1 but showing the bolt in initial contact with the cantilever spring; and

FIG. 3 is a view taken along line 22 of FIG. 2.

Shown in the figures is a firearm having a receiver 12 which houses a longitudinally reciprocal bolt 14 having a spring pressed firing pin 15. Bolt 14 is biased to a battery position by a compression spring 16. A pistol grip 18 depends from receiver 12 rearwardly of a trigger 20 having an integral sear 21 for releasably holding firing pin in a cocked position. Provided in receiver 12 forwardly of trigger 24) is a magazine well 22 arranged to receive a magazine 24 for holding a plurality of cartridges 26 respectively provided with a primer 27 set into the base thereof. Cartridges 26 are biased upwardly from magazine 24 into receiver 12 at a feeding position by a magazine spring 28.

Trigger is protected by a trigger guard 36 one end of which is received by a channel 32 that extends rearwardly in receiver 12 from well 22 along the inside of the receiver. Trigger guard 30 is fixed to receiver 12 at such end by screw means and is arranged to extend arcuately around trigger 20* in a semicircle with the opposite end anchored in the front side of pistol grip 18.

Trigger guard 30 is fabricated from flat spring stock and the top portion of the arcuate section is pierced to form a cantilever spring 34 which is integrally joined at the rear end to the trigger guard. Spring 34 is essentially of an S-configuration and is formed to extend upwardly in its free position into receiver 12. The front end of spring 34, noted at 36, is arranged, as shown in FIG. 2, to have contact with the base of the cartridge 26 which is pressed by magazine spring 28 into receiver 12 at the firing position to index such cartridge therein. The width of spring 34 is arranged to be wider than the diameter of primer 27 so that, when front end 36 contacts the base of cartridge 26, it spans the primer without contact therewith (see FIG. 3). Cantilever spring 34 is contactable by the front end of bolt 14 during movement to battery position so as to be cammed downwardly thereby and thereby loaded. During downward displacement of cantilever spring 34, front end 36 thereof is displaced with a forward component of movement against the base of the firing position cartridge 26 to initiate a forward displacement thereof into the chamber of a barrel 38 and thereby reduce the force of impact between bolt 14 and the cartridge when the bolt catches up therewith to complete the chambering operation. Cantilever spring 34 is also formed so that the upper arcuate section thereof, noted at 46, is contactable with the underside of bolt 14 during displacement thereof over magazine well 22 to reduce the frictional contact between the bolt and the cantilever spring and so that, when the cantilever spring is displaced downwardly by the bolt, front end 36 is pressed downwardly against the leading cartridge 26 in magazine 24. Thus, the leading cartridge 26 in magazine 24 is displaced downwardly free of contact by bolt 14 during dis placement thereof over the magazine.

Provided in the underside of bolt 14 in the rear end thereof is a holding surface 42 which inclines downwardly and forwardly from the rear end of the bolt and which is arranged for contact by arcuate section 46 when the bolt is in the battery position. Through the inclination of holding surface 42 and the combined forces of cantilever spring 34 and magazine spring 28 applied thereagainst through the cantilever spring (see FIG. 1), the bolt is held pressed against the chambered one of the cartridges to assure ignition of primer 27 thereof by firing pin 15 when released from the cocked position by trigger 26.

Thus, when bolt 14 is in battery position, the contact of cantilever spring 34 with holding surface 42 assists compression spring 16 in holding the bolt in battery to assure discharge of chambered cartridge 26 when trigger 20 is pulled to release firing pin 15. Also, front end 36 is pressed downwardly against the leading cartridge 26 in magazine 24 to hold such cartridge downwardly free of contact by bolt 14 and the bias of magazine spring 28 at the same time is transferred to cantilever spring 34 to increase the pressure applied thereby against holding surface 42.

Upon discharge of chambered cartridge 26, the case thereof sets back to energize bolt 14 for its cyclic function With the case being carried thereby by extractor means 44. When bolt 14 is clear of magazine 24 and the fired case is ejected from receiver 12, cantilever spring 34 is free to return to its normal position and thereby release the leading cartridge 26 in magazine 24 for displacement by magazine spring 28 to the feeding position in receiver 12. Front end 36 of cantilever spring 34 serves to index cartridge 26 in the feeding position by preventing rearward displacement thereto.

When bolt 14 proceeds in its counterrecoil stroke to battery opsition, cantilever spring 34 is contacted by the front end of the bolt to impart a forward thrust to cartridge 26 in the feeding position and to continue camming the cantilever spring downwardly so that front end 36 displaces the leading cartridge in magazine 24 downwardly free of the bolt. When bolt 14 reaches battery position, arcuate section 46 of cantilever spring 34 is in contact with holding surface 42 to retain the bolt therein.

From the foregoing it is clearly apparent that the combined cartridge indexing device, cartridge accelerating device, and the bolt holding device of this invention provide a firearm which is simple in construction, positive in operation, and inexpensive to manufacture so as to be expendable.

Although a particular embodiment of the invention has 3 been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. A firearm including a receiver, a bolt disposed for axial reciprocation in said receiver, a compression spring for biasing said bolt to a battery position, a magazine for holding a plurality of cartridges, a spring arranged in said magazine for biasing said cartridges therein successively to a feeding position in said receiver, a trigger guard, and a cantilever spring integrally formed in said trigger guard so as to extend normally therefrom into said receiver, said cantilever spring being designed so as to index the feeding position cartridge by preventing rearward displacement thereof when said cantilever spring is in its normal position, to accelerate the feeding position cartridge forwardly when said cantilever spring is contacted by said bolt during movement to battery position, and to depress the leading cartridge in said magazine downwardly free of said bolt when said bolt is positioned thereover.

2. The firearm as defined in claim 1 and including an arcnate section on said cantilever spring and a holding surface formed on said bolt so as to be resiliently contacted by said arcuate section when said bolt is in battery position and to cooperate with said arcuate section for transferring the combined force of said cantilever spring and said magazine spring to said bolt in a direction to hold said bolt in the battery position.

3. The firearm as defined in claim 1 wherein said cantilever spring is essentially of an S-configuration and in cludes a front end arranged for contact with the base of the cartridge in the feeding position to prevent rearward displacement of the feeding position cartridge and to accelerate the cartridge forwardly when said cantilever spring is contacted by said bolt during displacement thereof to the battery position.

4. The firearm as defined in claim 1 wherein said cantilever spring is essentially of an S-configuration and is arranged to normally extend upwardly into said receiver from said trigger guard for contact by said bolt during displacement to battery position and wherein said cantilever spring includes a front end located so as to be contactable by the base of the cartridge when moved into the feeding position from said magazine to index said cartridge thereof and to be displaceable with a forward component of movement against the feeding position cartridge when said cantilever spring is contacted by said bolt during displacement to battery position, and said front end is displaceable against the leading cartridge in said magazine for downward displacement thereof free of said bolt when disposed over the magazine.

5. The firearm as defined in claim 4 wherein said bolt is provided with an inclined holding surface and said cantilever spring also includes an arcuate portion which is arranged for contact with the underside of said bolt during displacement of said bolt thereover and for contact with said holding surface so as to transfer the bias of said cantilever spring to said bolt in a direction to hold said bolt in the battery position.

No references cited. 

1. A FIREARM INCLUDING A RECEIVER, A BOLT DISPOSED FOR AXIAL RECIPROCATION IN SAID RECEIVER, A COMPRESSION SPRING FOR BIASING SAID BOLT TO A BATTERY POSITION, A MAGAZINE FOR HOLDING A PLURALITY OF CARTRIDGES, A SPRING ARRANGED IN SAID MAGAZINE FOR BIASING SAID CARTRIDGES THEREIN SUCCESSIVELY TO A FEEDING POSITION IN SAID RECEIVER, A TRIGGER GUARD, AND A CANTILEVER SPRING INTEGRALLY FORMED IN SAID TRIGGER GUARD SO AS TO EXTEND NORMALLY THEREFROM INTO SAID RECEIVER, SAID CANTILEVER SPRING BEING DESIGNED SO AS TO INDEX THE FEEDING POSITION CARTRIDGE BY PREVENTING REARWARD DISPLACEMENT THEREOF WHEN SAID CANTILEVER SPRING IS IN ITS NORMAL POSITION, TO ACCELERATE THE FEEDING POSITION CARTRIDGE FORWARDLY WHEN SAID CANTILEVER SPRING IS CONTACTED BY SAID BOLT DURING MOVEMENT TO BATTERY POSITION, AND TO 